Projection systems, or projectors, are generally devices that integrate light sources, optics systems, electronics, and spatial light modulators for projecting data such as images, video, documents, and spreadsheets from computers or video devices onto walls or front or rear screens, for large-image viewing. They are popular among business users who give presentations as part of their job responsibilities. Projectors are also finding their way into peoples' homes for high-definition television (HDTV) and other home entertainment applications.
To ensure the highest image quality, projectors typically include sophisticated projection lenses. These sophisticated lenses have high resolution, low distortion and lateral color, large field of view, high offset, and high uniformity, in addition to zoom and focusing features. Such projection lenses are often large in size and sometimes very expensive. Furthermore, it can be difficult to implement large zoom ratios and provide large adjustable offsets within such sophisticated lenses.